Recalcitrant paradoxical pustular psoriasis induced by infliximab: Two case reports

Table 1 Changes of anti-nuclear antibodies during infliximab treatment

Time of infliximab treatment	Baseline	8 wk	Outbreak of pustulosis	During 3 mo of follow-up
Case 1	Negative	1: 100	1: 320	Negative
Case 2	Negative	–	1: 1000	1:320

Table 2 Changes in blood-test results before and after the rash during infliximab treatment

Rash	N/L		CRP, 0-5 mg/L		ESR, 20 mm/H		Cytokines
	Before	After	Before	After	Before	After	Before	After
Case 1	1.20	4.28	< 3.23	30.1	27	105	TNF-α: 165.00 pg/mL, IL-8: normal	TNF-α: 202.00 pg/mL, IL-8: 81.80 pg/mL
Case 2	4.07	4.58	< 3.23	10.4	12	23	–	TNF-α: 84.80 pg/mL

CRP: C-reactive protein; ESR: Erythrocyte sedimentation rate; N/L: Neutrophil/lymphocyte ratio; TNF-α: Tumor necrosis factor-alpha.

Table 3 Common differentials of pustular psoriasis

	Presentation	Histopathology	Etiology and pathoimmunology
Acute generalized pustular psoriasis	Widespread formation of sterile pustules with erythema on the trunk and limbs. Pustules often expand into lakes of pus. Relapsed course	Overall epidermal architecture similar to plaque psoriasis. Formation of intra-epidermal neutrophilic abscesses, with marked dermal infiltrate composed of neutrophils, monocytes, and T-lymphocytes	Infection, stress, corticosteroid (treatment withdrawal). IL36RN mutation[6]
Palmoplantar pustulosis	Scattered clusters of pinhead-size sterile pustules on the palms and soles. Chronic course	As GPP	Genetic, roles of nicotine and contact allergens, certain medications and stress[7]
Acute exanthematous generalized pustular eruption	Polymorphous eruption more prominent than psoriasis, short duration, and no subsequent relapsing course	Necrotic keratinocytes and eosinophils are common	Drugs, notably anti-infectious chemotherapy, also non-steroidal anti-inflammatory drugs[8]

GPP: Generalized pustular psoriasis.